[计] switched telecommunication network

jiāo huàn xíng yuǎn chéng tōng xìn wǎng luò ㄐㄧㄠ ㄏㄨㄢˋ ㄒㄧㄥˊ ㄩㄢˇ ㄔㄥˊ ㄊㄨㄥ ㄒㄧㄣˋ ㄨㄤˇ ㄌㄨㄛˋ